CR-1732: Fix "issn" parsing
Here's how "issn" relationship of the ItemTree looks in Manifold before it's passed to Cayenne:
Relationship(
relTyp=issn,
obj=Item(
identifiers=[],
rels=[],
properties=[Properties(values={"kind":"electronic","type":"id","subtype":"issn","original":"0264-3561"},
assertedBy=Item(identifiers=[Identifier(uri=https://id.crossref.org/org/7822, type=CROSSREF_ORG, pk=null)], rels=[], properties=[], pk=10),
assertedAt=2022-03-13T11:15:56Z)],
pk=null),
assertedBy=Item(identifiers=[Identifier(uri=https://id.crossref.org/org/7822, type=CROSSREF_ORG, pk=null)], rels=[], properties=[], pk=10), assertedAt=2022-03-13T11:15:56Z, relTypePk=112)
Specifically, notice that in properties we only have "original", and not "id". I'm not sure this is the correct fix, or if this was done on purpose, but unit test changes seem to suggest it was a bug.
Edited by Dima Safonov